Regulation 4(1)
1. An accident resulting in the death of a person or the serious injury of two or more persons.
2. An accident on a level crossing involving rolling stock, resulting in the death of a person or serious injury to a person.
3. A collision between rolling stock on a running line which causes damage or blocks a running line that was open to railway traffic at the time of the collision.
4. A derailment of rolling stock on a running line that was open to railway traffic at the time of the derailment, or which blocks a running line that was open to railway traffic at the time of the derailment.
5. A collision of rolling stock with an arrestor mechanism or buffer stop, other than in a siding, that causes damage to the rolling stock.
6. An accident involving the release or combustion of dangerous goods being carried on rolling stock that necessitates the evacuation of the area.
7. An accident or incident that is likely to result in suspension of a railway service for a period in excess of 6 hours.
8. An accident that causes extensive damage to rolling stock, the infrastructure or the environment.
9. An accident or incident which under slightly different conditions might have led to a death, serious injury or extensive damage to rolling stock, the infrastructure or the environment.